AB-INITIO MOLECULAR DYNAMICS IN THE FULL-POTENTIAL LMTO METHOD: DERIVATION OF A PRACTICAL FORCE THEOREM

1993 ◽  
Vol 07 (01n03) ◽  
pp. 262-265 ◽  
Author(s):  
M. METHFESSEL ◽  
M. VAN SCHILFGAARDE
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Local Density ◽  
Basis Set ◽  
Ab Initio Molecular Dynamics ◽  
Basis Sets ◽  
Full Potential ◽  
Major Advance ◽  
First Results ◽  
Lmto Method

A major advance in electronic structure calculations was the combination of local-density techniques with molecular dynamics by Car and Parrinello seven years ago. Unfortunately, application of the Car-Parrinello scheme has been limited essentially to sp materials because only in the plane-wave pseudopotential method forces are trivial to calculate. We present a systematic approach to derive force theorems with desired characteristics within complicated basis sets, which are applicable to all elements of the periodic table equally well. Application to the LMTO basis set yields an accurate force theorem, quite distinct from the Hellman-Feynman form, which is exceptionally insensitive to errors in the trial density. The forces were implemented in a new full-potential LMTO method which is suited to arbitrary geometries. First results for ab-initio molecular dynamics and simulated annealing runs are shown for some random small molecules and small clusters of silver atoms.

Electronic Structure and Bonding Nature of the Ground State Monocarbide Cations, ScC+, TiC+, VC+, and CrC+

2003 ◽  
Vol 68 (2) ◽  
pp. 387-404 ◽  
Author(s):  
Ioannis S. K. Kerkines ◽  
Aristides Mavridis
Keyword(s):  
Ground State ◽  
Ground States ◽  
Relativistic Effects ◽  
Zero Point ◽  
Basis Set ◽  
Basis Sets ◽  
Energy Separation ◽  
Full Potential ◽  
Complete Basis Set ◽  
Correlation Consistent

The ground states of the transition-metal diatomic carbide cations, MC+ (M = Sc, Ti, V, and Cr), are studied using multireference configuration interaction (MRCI) methods in conjunction with quantitative basis sets. Full potential energy curves are calculated for all four systems. When 3s23p6 core/valence correlation contributions and scalar relativistic effects are taken into account, our best estimates for the zero-point-corrected dissociation energies of the MC+ series are in good agreement with relevant experimental results. For TiC+, the recent correlation-consistent-type basis sets for Ti of Bauschlicher are also exploited to extract complete basis set limits of selected properties. The ground states of VC+(X 3∆) and CrC+(X 2∆) are reported for the first time in the literature. For CrC+ an interesting competition is revealed between the 2∆ and 4Σ- states; although 4Σ- is formally the ground state at the MRCI level of theory, when core/valence and/or relativistic effects are included, the ground state of CrC+ becomes of 2∆ symmetry, with a calculated energy separation (a 4Σ- ← X 2∆) of 2.3 kcal/mol.

Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

1978 ◽  
Vol 36 (3) ◽  
pp. 470-482 ◽  
Author(s):  
R.W. Horne
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Analytical Techniques ◽  
Staining Technique ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Full Potential ◽  
Virus Particles ◽  
Resolution Electron ◽  
Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

“High Resolution High Voltage Electron Microscopy”

1968 ◽  
Vol 26 ◽  
pp. 326-327
Author(s):  
Benjamin M. Siegel
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Voltage ◽  
Full Potential ◽  
Contrast Imaging ◽  
High Voltage Electron Microscopy ◽  
Low Contrast ◽  
Voltage Electron ◽  
Critical Areas ◽  
High Voltage Electron

The potential advantages of high voltage electron microscopy for extending the limits of resolution and contrast in imaging low contrast objects, such as biomolecular specimens, is very great. The results of computations will be presented showing that at accelerating voltages of 500-1000 kV it should be possible to achieve spacial resolutions of 1 to 1.5 Å and using phase contrast imaging achieve adequate image contrast to observe single atoms of low atomic number.The practical problems associated with the design and utilization of the high voltage instrument are, optimistically, within the range of competence of the state of the art. However, there are some extremely important and critical areas to be systematically investigated before we have achieved this competence. The basic electron optics of the column required is well understood, but before the full potential of an instrument capable of resolutions of better than 1.5 Å are realized some very careful development work will be required. Of great importance for the actual achievement of high resolution with a high voltage electron microscope is the fundamental limitation set by the characteristics of the high voltage electron beam that can be obtained from the accelerator column.

Instant 99mTc Compounds

1971 ◽  
Vol 10 (03) ◽  
pp. 245-251 ◽  
Author(s):  
P. Richards ◽  
W. C. Eckelman
Keyword(s):  
Physical Properties ◽  
High Purity ◽  
Analytical Techniques ◽  
Full Potential ◽  
Labeled Compounds ◽  
Ph Adjustment ◽  
One Step ◽  
Stannous Ion ◽  
99Mtc Radiopharmaceuticals ◽  
Potential Use

SummaryThe full potential use of technetium has not been achieved despite its ideal physical properties, dosimetry and availability because of the complex preparations required for 99mTc radiopharmaceuticals. One of the goals of our work is to develop techniques for the preparation of high-purity 99mTc compounds which can be easily prepared, ideally by adding pertechnetate to a prepared solution.The use of stannous ion as reducing agent for technetium makes it possible to obtain such one-step, high-purity products. All non-radioactive components can be premixed in a single vial before addition of the radioactive pertechnetate. No final pH adjustment, further chemical manipulation or purification is required.Procedures for two instantly labeled compounds have been developed to date: 99mTc DTPA and 99mTc HSA. The 99mTc DTPA is prepared by adding pertechnetate to a previously prepared solution of stannous ion and CaNa3 DTPA which has been stored at pH 4. The 99mTc HSA is prepared by adding pertechnetate to a solution of stannous ion and HSA. The parametric variations and analytical techniques involved in formulating these procedures are described. It appears that development of kits for other biologically interesting compounds may be possible using similar procedures.

Intelligent Processing of Loosely Structured Documents as a Strategy for Organizing Electronic Health Care Records

1993 ◽  
Vol 32 (04) ◽  
pp. 265-268 ◽  
Author(s):  
D. J. Essin
Keyword(s):  
Health Care ◽  
Health Care Organization ◽  
Database Systems ◽  
Relevant Information ◽  
Full Potential ◽  
Care Organization ◽  
Intelligent Processing ◽  
Data Interchange ◽  
Structured Documents ◽  
Health Care Records

AbstractLoosely structured documents can capture more relevant information about medical events than is possible using today’s popular databases. In order to realize the full potential of this increased information content, techniques will be required that go beyond the static mapping of stored data into a single, rigid data model. Through intelligent processing, loosely structured documents can become a rich source of detailed data about actual events that can support the wide variety of applications needed to run a health-care organization, document medical care or conduct research. Abstraction and indirection are the means by which dynamic data models and intelligent processing are introduced into database systems. A system designed around loosely structured documents can evolve gracefully while preserving the integrity of the stored data. The ability to identify and locate the information contained within documents offers new opportunities to exchange data that can replace more rigid standards of data interchange.

Arguing for Design Thinking Interventions as a Form of Artistic Interventions

2016 ◽  
Vol 10 ◽  
pp. 40-47
Author(s):  
Ulla Johansson Sköldberg ◽  
Jill Woodilla
Keyword(s):  
Organizational Change ◽  
Design Thinking ◽  
Organizational Innovation ◽  
Frame Of Reference ◽  
Full Potential ◽  
Artistic Process ◽  
Theoretical Frame ◽  
Artistic Interventions ◽  
Innovation And Change ◽  
Empirical Material

Drawing on data from two projects where artists used their artistic competence as organizational change facilitators, we argue for a theoretical coupling of the discourse(s) of design thinking to research streams within art-and-management. The artistic dimension of design, the practice perspective and the artistic process should be considered if we are to understand the full potential of design thinking for companies. This paper describes two artistic intervention projects that highlight valuable ways artists can contribute to organizational innovation and change.  We begin with the theoretical frame of reference and a short methodological statement, followed by the empirical material.  In the analysis section we point to ways in which such interventions are similar to ones led by designers when we consider the designer’s process as individualized and contextualized.  Finally, we draw conclusions.

Preparation, Electronic Structure and Optical Properties of the Electrochromic Thin Films

2004 ◽  
Vol 9 (4) ◽  
pp. 363-372 ◽  
Author(s):  
T. Lukaszewicz ◽  
A. Ravinski ◽  
I. Makoed
Keyword(s):  
Electrochromic Device ◽  
Orbital Method ◽  
Optical Parameters ◽  
Full Potential ◽  
Electrochromic Devices ◽  
Energy Bands ◽  
Conducting Film ◽  
Recombination Probability ◽  
Transparent Conducting ◽  
Smoluchowski Equations

A new multilayer electrochromic device has been constructed according to the following pattern: glass1/ITO/WO3/gel electrolyte/BP/ITO/glass2, where ITO is a transparent conducting film made of indium and tin oxide and with the surface resistance equal 8–10 Ω/cm2 . The electrochromic devices obtained in the research are characterized by great (considerable) transmittance variation between coloration and bleaching state (25–40% at applied voltage of 1.5 to 3 V), and also high coloration efficiency (above 100 cm2 /C). Selfconsistent energy bands, dielectric permittivity and optical parameters are calculated using a full-potential linear muffin-tin orbital method. The numerical solution of the Debye-Smoluchowski equations is developed for simulating recombination probability of Li+ ions in amorphous electrolyte.

Evolution of the electronic structure of metallic multilayers from two to threedimensionality. A Full Potential Linearized Augmented Plane Wave calculation.

2002 ◽  
Vol 727 ◽  
Author(s):  
A. M. Mazzone
Keyword(s):  
Plane Wave ◽  
Density Of States ◽  
Noble Metals ◽  
Full Potential ◽  
Metallic Multilayers ◽  
Augmented Plane Wave ◽  
Narrow Bandwidth ◽  
Epitaxial Multilayers ◽  
Linearized Augmented Plane Wave ◽  
Wave Calculation

AbstractFull Potential Linearized Augmented Plane Wave calculations have been performed for epitaxial multilayers formed by the noble metals Ag and Cu with a thickness n up to 10 layers. The multilayers have a fcc lattice and are pure or compositionally modulated with a structure of the type Agn Cun or (AgCu)n. For n in the range 2,3 the density of states, evaluated at paramagnetic level, exhibits a sharp reduction of the bandwidth which is consistent with the reduced coordination of these structures. For n ≤ 5 the density of states in the central layers converges to the bulk value while the outer layers retain the narrow bandwidth found at n=2. Due to the absence of charge intermixing and hybridization, these features are shared by multilayers of all composition.

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